1. Field of the Invention
The invention relates in general to an antenna, and more particularly to a planar inverse-F antenna (IFA).
2. Description of the Related Art
As science and technology have gained rapid advance nowadays, a large variety of compact antennas have been developed and applied in various electronic devices such as mobile phones and notebook computers. For example, the planar inverse-F antenna (PIFA), which has a compact structure and excellent transmission efficiency and can be easily disposed on an inner wall of an electronic device, has been widely applied in the wireless transmission of many electronic devices. However, most of conventional PIFAs are single band antenna, and can only support a narrower frequency band.
For example, the grounding signal and the signal to be transmitted through the PIFA are respectively transmitted through the exterior conductor layer and the interior conductor layer of the coaxial cable. According to the conventional technology, the exterior conductor layer and the interior conductor layer of the coaxial cable are often soldered to the signal feeding point and the signal grounding point of the PIFA respectively for outputting the to-be-transmitted signals through the PIFA. However, the conventional technology is disadvantaged by the problems that the coaxial cable may come off easily and incurs more cost.